In the case that a stereo image is displayed, there are known, for example, a technology using polarized glasses and a technology using a lenticular lens. However, in the former case, it is annoying to wear the polarized glasses. On the other hand, in the latter case, although there is no annoyance to wear the polarized glasses, a reduction in resolution can be a problem. Moreover, both technologies require the preparation of parallax images corresponding to both eyes of a viewer in advance. In order to deal with such a problem, for example, there has been suggested a technology represented by a 3D floating vision (registered trademark by the present inventors) method (refer to a patent document 1).    Patent Document 1: Japanese Patent Application Laid Open No. 2003-333623